Apparatus for quick freezing food products



I vof apparatus.

' ucts and cooling mediumrespectively.

' Patented' Mar. 24, 1942 1 UNITE-D STATES lMEN'l* oFFlcE'-,

ArrAm'rUs FOR. QUICK FREEZINGZFOOD PRODU lom c. Butz, Jeffers@ city, Mo. Application December 1, i937, serial No. 171,565 4 claims. (cica-.102i

This linvention relates to refrigeration, moreparticularly to an improved method of and apparatus'A for quick freezing food products.

' In recent years there has been a marked, V increase in the use of refrigeration for preserving fresh, perishable foods; A notable example is the expanding use of quick freezing processes for preserving different varieties of fresh vegetables, meats, and the like. The potential use of such methods, however, is restricted seriously because of the large space requirements andthe relatively low eiliciency ofthe units suggested heretofore.' In typical earlier systems, the method employed involved the utilization of separate prechilling and freezing stageswith a commensurately largeover-all plant size, as well las ma'- nipulative complications in maintaining differential thermal conditions in such stages.

for the refrigeration of fully draui, fresh chickens will be described. g It will be vppreciated that in such a system the major problems` of quick freezing of food productsare present to an accentuated degree For example, in the quick freezing of such poultry, care must be exercised to insure the effective abstraction of the body The utilization of the quickfreezing principle could be extended very considerably if there'was available for .potential users a simple, compact,

' such products.

self-contained apparatus, and particularly one in which the refrigeration effect could be adjusted within rather wide limits so as to permit employ` A v ment for diierent types of products.

As a result of considerable'experimentation, I

.have devised a novel method of sharp.freezing,

4heat of the product prior to the reduction of its Aswill be seen more fully, the present lmethod .involves-thepassage of the products4 to be treated i through a series of narrow, elongated, respectivelyadjacent, sinuous passageways and while in contact 'with astream of positively circulating,

` cold air;J whichlatter n ows countercurrent to the operating upon a continuous counteriiow princlple and in which-the path ot travel -oftheprodj ucts to be treated is correlated'in a novel man-1 ner with the refrigeration apparatus fand with the-ow of refrigerated air, so as toinsure .an optimum refrigeration effect in a` minimum size In'order to enable a more ready comprehension ofthe invention, preferred physical embodiments of the underlying principlesa are illustrated in the apparatus shown in the accompanying drawings, in which:

Figure l is'a top sectional' vie'w showing the essential elements of the system.'

Figure 2 is .a vertic 2-2- of Figure 1. e

Figure 3` is a horizontal section through the structure taken on line 3`-'3 of Figure 2..

Figure 4 is a cross section taken on line 4-"4'61' Figure 1.

al section taken on line v'freezing ofthe product is effected. It Awill also products. The unit'i's so designed that prior to dischaxge,"the products are contacted with air .at the minimum temperature and such air, in its counteriiow continuously abstracts heat from the product to be frozen. -Such' products enter the unit, preferably at a point closely adjacent the -point ofA discharge,`and are thus contacted with the warmer air. which latter then passes in heatv exchangerelationship to a refi'igeratingmedium and is recycled through the system. It is particularly to be observed that the ow of. airinV heat exchange relationship to the refrigerating unit'is preferably substantially normal' to the Ailow of air through the passageway, in which be observed that the air which is utilized to con- Figure 5 is a diagrammatic illustration showi ing the path of flow of the products to be treated,

withrespect to'the ilow of thecooling medium.

Figures 6 and? areA views similar to Figure 5,` showing modiilcationsof the paths of the prod- .In order more clearly to explain the invention,

,an apparatus which has been designed especially tact with and abstract heat from the products is extenuated in a relatively narrow stream. In these circumstances, maximum heat transfer as between the air and the'refrigerant, on the one hand, and the air and the productsv to be frozen, on the other, is achieved. It willalso be observed that further thermal economies"are attainedby utilizing the concept ofthe relatively long, narrow andv respectively adjacent passageways'. In

' these circumstances, the dilerential in tempera'- ture on the opposite sides of the partitions is 5.5 maintained at a low value and heat transmission erating machine.

therethrough is commensurately diminished. These and other advantages will-be more readily appreciated from a consideration of a preferred type of unit.

As shown in the drawings, the apparatus includes a main chamber i in which the actual freezing is effected; an antechamber 2, serving to house certain of the refrigerating apparatus and mechanical driving mechanism, and a receiving or storage room 3, in which the frozen articles may be processed, packed, or otherwise treated.` As shown in Figures 1 and 3, the above described chambers may be associated with other structures such for example as the receiving room 4, of an existing building, or the like. Since the essential function of sharp freezing is accomplished by the mechanism housed in chambers I and 2, it will be appreciated that these two chambers may be, and preferably are constructed as a separate entity, adapted for employment alone or adapted to be associated with existing structures, as for example, with an existing building provided with an ammonia refrig- Since the unit is reduced to an eminently compact structure, it may be employed as by being mounted on a truck or trailer to serve as a mobile unit. In these circumstances, as will be appreciated, some of the power required in the operation, as for example, that necessary to drive the conveyor and/or the blower, may be taken oil' from the automotive power plant of the vehicle. When the unit is utilized with a mobile vehicle, such as a truck or train, it will be understood that it may be operated while the vehicle is in transit and/or while the Vehicle is temporarily located at some particular point.

' The unit is constructed of suitable materials in a manner well known to those skilled in the art. Thus the unit may comprise the side walls 5 and 5, end walls 'I and 8, and the bottom and top walls Il and I2, respectively. As shown the outer Walls consist of sheathing I3 of suitable weather resistant material, such as metal, protectively coated wood, and the like. The inner walls 21:3 are spaced some considerable distance from the outer walls and the space therebetween is'lled with material of high insulating value, such as cork board and the like. This construction is to insure the maximum insulation and for this purpose, the cork insulation lling may be of the order of 12 inchesthickymore or less. The interior walls Il are-composed of any suitable moisture-resistant material, such as metal, Bakelite impregnated or coated boards, and the like; in short, any suitable material which is sufciently Amoisture-resistant so as to preclude the possibility of moisture pick-up in the insulation material. c y

The anteroom 2, as shown, may be provided with a door 20, so as to provide access to the accumulator tank, conveyor mechanism, or other units housed there. The side wall 5, if desired, may belprovided with the door` 2| so as to provide access to the conveyor for the purpose of inspection, repair, and the like.

The receiving or storage room 3, as shown, is similarly provided with the door 22. As will be noted from an inspection of Figures 1 and 3, the main unit, comprising the chambers I and 2, are thoroughly insulated so that heat losses are reduced to the minimum.

The freezing chamber itself comprises in effect two sections. One such section is the centrally located-refrigerator per se. This .is Shown as comprising the bunker or bank of expansion coils 30. Such expansion coils arehoused within the interior chamber comprised of the end wall 25, the side wall 26, and the top wall 2l'. The end wall 25 is a substantially solid wall, whereas the side wall 26 and top Wall 2l are provided with apertures, more fully to be described, so as to provide for the recirculation of air to and from this interior chamber.

As will be observed, particularly in Figure 3, the bunker chamber is positioned substantially centrally with respect to the remainder of the chamber I. Such remainder comprises, as shown, a series of narrow, elongated, angular passageways. As will be seen, with particular reference to Figure l, such chamber is divided into two L shaped and respectively adjacent passageways by means of the angular partitions 30 and 3 l The partition 3l (see Figures 1 and 2) extends vertically from the bottom to the tcp of chamber i, whereas the partition 3G extends vertically from the bottom of the chamber to the extension of top wall 2l (see Figure 4). As shown, particularly in Figure 1, the partition 3U' extends horizontally from the side wall 3 to the partition 3i, While the latter terminates some distance short of the side wall I3. In these circumstances, the cooling chamber is divided into a series of communicating passageways. The rst section, A, of such passageway is a plenum chamber, confined by the top wall li of the unit and the top wall 2l of the bunker chamber. As will be observed from an inspection of Figure 4, this plenum chamber is in open communication with the vertically narrowed, horizontally elongated passageway B, defined by a side wall 5 of the unit and the partition 3U'. Such passageway section B is continued as an angular extension or passageway section C, the latter being established between the end wall I and the partition 3l. Such latter passageway 'section in turn communicates with the respectively adjacent passageway section D, this latter being defined by the end wall 25 of the bunker chamber and the partition 3l. The section D is continued as an angularly disposed passageway section E, defined by the partition 3D and the side wall 2S, and the bunker unit.

As shown particularly in Figure 1, the side wall 26 is shortened adjacent the wall il or is provided with apertures, louvres or other openings, so as to establish uid communication between the passageway section E and the interior of the bunker chamber. lIn the preferred form of construction, the expansion coils 30 are associated with a series of baffles 40, 4| and 42, so as to define, in effect, a sinuous course for air flow over the expansion coils.

As has been explained hereinbefore, a salient feature of the present invention is the fact that the products or materials to be frozen are passed in'heat exchange counterilow relationship with the cold air. For this purpose, any suitable type of conveyor mechanism, the speed of which may readily be controlled, may be employed. A diagrammatic illustration of such unit is shown more particularly in Figure 1. As there shown, the conveyor may be driven by any suitable source of power, such as the motor 50. Such motor connects through a gear reduction unit 5l with the driving pulley 52 of the conveyor. Associated with driving gear 52 are a series of idler pulleys 53, 54, 55 and 5S. A suitable con- .veyor belt, chain, or the like, indicated diagrammatically at 51, passes over the driving pulley 52 andthe several idler pulleys. The pulley I, as

shown, is preferably enlarged in'size and .is pro- Yvided with means, such as the spring 58, whereby any predetermined resilient tension may be established on the conveyor system. The conveyor systemmayinclude a series of tracks 58, supported by hangers 59,- on 'whicl'r individual rack units may move through the passageways.

. In accordance with the principles expressed herein, the products to be frozen are transported .l0

by the conveyor system from' one point through the series of angularlyfdisposed, communicated passageways and are discharged from such passageways under lthe optimum temperature condi# tions at a point adjacent the point of entry. For this purpose, thexwall "is` -provided with a small opening or feeding' door 60, through which an operator may insert the products to .be treated so as to be mounted on the conveyor system. Similarly, the storage chamber 3 communicates with the `main freezing chamber through the medium ofthe smalll passageway 6I. By reason of this opening, an operator may remove frozen products from the conveyor belt orsystem fox packaging or storage in the storage chamber 3. As has been'indicated vhereinbefore, provision is made for positively circulating air over the expansion coil and through the several conncting passageways. tAs shown particularly in Figures 3 and 4, such circulation is eiected by means of a series' of blowers or fans 10, positioned above and at one side of the bunker chamber. Such blowers are driven by means of a suitable driving mechanism, such as the motor 1I,

vwhich is connected to the blower drive'shafts 12.

l The blowers are suitably housed on the bunker roof 21, as by means ofthe walls 13 and 1l. As

will be observed vfrom an inspection of Figure 3,'

the top section or roof 21 of the bunker chamber is provided with a series of apertures 15 which establish communication between the bunker and the fan housing. In these circumstances, the

blowers draw air through the bunker chamber and over the expansion coil and then discharge chilled air into the plenum chamber. Recircuenlarged, apertures 16 in the wall 26, whichit will be noted, is adjacent the point of inlet of the products to be treated.

The length oi' the expansion coil 30, or more strictly thecooling capacity'of the refrigeration unit, 'is established to satisfy the cooling requirenents of the particular use -for which the unit s intended. .Within the bunker chamber there s provided a condenseror drip pan 80..

It will be understood that the expansion cjoil 30 comprises yanelement in a typical direct expansion system, utilizing a volatile liquid such as of branch 95 through a scale separator or other clarifying device to the suctionside ofthe compressor. After passing through the compressor and condenser, in the -well known manner, the liquied refrigerant is re-admitted through line 9| to be recycled. The operation of valve 93 may be controlled thermostatically to meet the requirements for any particular installation. A When the present system is employed for refrigeration purposes which require very low temperatures, ity may be coupled up as an additional refrigeration cycle with a pre-existing refrigeration apparatus. Such a serial connectionl will` readily'be understood and can well be made by' The conveyor mechanism for. transporting the articles to be frozen maybe of any suitable or desired type, such. for example, as that more particularly described and shown in. my learlier Patents No. 1,955,668 and N0.1,955,669.

With this type of structure. it will be seen that effective recirculation of air through the cooling unit is insured and that, in such recirculation,`

the air is caused to positively flow through a series of angulanelongated passageways, countercurrent to the incoming products which are to' be frozen. In the drawings; air flow is indicated by the full-line arrows, and the path of the products to be frozen by the broken line arrows. It will thus ebe seen that relatively warm airis sucked` in under the action of the blowerslllu, through the apertures or louvers 1S, into the bunker chamber. 'I'his air is then constrained,

by reason of the baffles, to pass longitudinally in a sinuous passage. over the bank of expansion coils. In this passage the retrigerantwithin the coils abstracts heat from the circulating air, re-

ducing the temperature of the latter down to a low point. Such air, after vthis drastic cooling' is then forced underv the action of the fans through the plenum chamber -A, and is dis' .charged as shown in Figure 4) into the passageway B. It will be noted thatthe passageway B lating air is admitted to the bunker through` the constitutes the' ylatter portion of the path of travel of the products to be frozen. In these circumstances, therefore, just prior to discharge ammonia. As shown, the storage tank `oraccu- A mulator is `suitably connected, as through a line 9|, to thecondenserand compressor of a typical refrigeration cycle. vThe condenser, compresser. and lines have been omitted so as to.

clarify the drawings. The construction and association of theseelements each' with. the other 'is well known to those skilled -in the art. The

. storage tank or accumulatorqsll is connected l throughthe line 92 and expansion or throttle valve 93, to the expansion coil 30. In the manner.we1l known to those skilled in' the art, the

from the unit, the articles beingfrozen are contacted with positively circulated air at the minimum temperature. The -air forced into passage- Contemporaneously, the materials to b 'e frozen are admitted into the passageway E and are passed thence sequentially through passageways D, `(I and B in airflow.

It is particularly to be Yobserved that in the countercurrent direction the present operation the clean, fresh air is recycled to and 4from the bunker. In operatiorrof the unit,`therefore, after a predetermined numberl -zofl such cycles or passages, the temperature of cool, liquied ammonia passing through valve 93 is .reduced 'in -pressure and volatilized. In its discharged from Vthe expansion coil passes .passage through, theiexpansion coil, it abstracts heat from the surroundingvmedium.- The vapor f7 air is materially reduced with consequent reduci. tion in weight loss,A due to dehydration of the the air is reduced to a pointwhere it is not materially' in excess of the .refrigerant passing through 'the con so. with'sueh a diminutionlin the temperature differential, dehydration of the product to be processed.

of the unit described Yherein is for quick freezing fresh. full drawnpo'ultry. In order to supply fully drawn poultry'to the trade, in which,

y As intimated hereinbefore, one 'preferred use l' poultry is preservedl the natural flavor, itis nec- .essary to refrigerate vin .agve'ryshorttimeyafterIv killing. It is a fact that fully drawn poultry tends to deteriorate more quickly than the socalled New York dressed poultry. This is probably due to the fact that a considerable area of the more readily decomposable flesh is exposed to the air. Whereas, in New York dressed poultry, the entire product is covered and protected by the original epidermis, in fully dressed poultry only a portion of the ultimate exposed area is covered and hence protected by the epidermis, the remainder being comprised of the vascular subcutaneous tissue, from which there is a greater tendency to loss of body moisture by evaporation and which tissue is also more susceptible to deterioration.

In the proper refrigeration of such'products, therefore, the refrigeration process must carefully be controlled so as to insure a quick and effective removal of the residual body heat and subsequent sharp or drastic freezing without undue loss of weight and consequent impairment of texture and flavor.` In the present improved body heat is largely abstracted and dehydration 1 minimized. As is explained in prior patent No.

method, the special type of air recirculation, in

tioning of the present unit and for the purposel of producirg refrigerated freshly drawn poultry, the structure is so devised and operated that air is dscharged from the bunker into passage B, at a temperature of the order of from 40 F., or above, to 60 F.. or below. For this particular type of refrigeration, the total length of the conveyor system may be of the order of feet or more. The speed of the conveyor is preferably adjusted so that the products pass through the refrigerating passageway at a speed of the order of 6 inches to 14 inches per minute. In these circumstances therefore, the complete refrigeration cycle is completed in from one-half to one hour, during which time the product is prechilled and then brought down to an ultimate temperature of the order of below zero. With this type of process, it is possible to freeze two hundred one-pound broilers in from 30 to 60 minutes. It will be understood, of course, that the length of travel of the products, through the passageway, and the speed of the conveyor is adjusted with respect to the character and size of the products to be treated and the ultimate temperature to which they are to be reduced.

In operating the unit, as already indicated, the freshly drawn chickens which are accumulated in the room 4 are placed upon the conveyor by means of suitable detachable racks, baskets, and the like, as by feeding the poultry through the door 60. Such poultry then enters the -freezng chamber section defined by the side walls 20 and 8 in which they are first contacted with the warmer air escaping into the chamber from passage B. This chamber is in effect a prechilled room in which relatively cool and quiescent air is maintained. It is particularly to be noted that this room is not directly included in the positive air circulation cycle and hence the air therein' is relatively still or quiescent; During Athe passage of the poultry through this prechilled room the 1,955,669, the poultry are so disposed and spaced on the conveyor that there is no possibility of contact of the adjacent units, so that free circulation of air over the entire surface of each unit and, hence, uniform freezing is insured. In the early phase of travel, thebody heat is abstracted and, as the products pass into the progressively cooler areas, the temperature is cornmensurately reduced such that when arriving at the discharge point (pulley 52) they are reduced to the desired ultimate temperature. At this point they are removed from the conveyor and may then be packaged or otherwise treated in the storage room 3. It is found that with this type of treatment, fresh, fully drawn poultry may be refrigerated or frozen down to the temperatures'of the orders stated. With such an established low temperature, these products may be packaged in suitable containers, such as cardboard, or other units of reasonably good insulation value, and may be shipped to distant points without further refrigeration.

It willrbe appreciated that what has been said of the treatment of freshly drawn poultry applies'generally to other products which are desired to be preserved under the present method, it being understood that it is only necessary to make the requisite adjustments as to speed of travel, conveyor length, and temperature of the air, so as to adapt the system to the products to be frozen.

In the type of apparatus thus far described, the refrigerating chamber, per se, comprises essentially two narrow, L-shaped passageways, which are associated with a substantially cen trally positioned expansion coil or bunker chamber. It will be appreciated, however, that within -theY concept of the invention, other specifically different associations of passageways may be availed of. As an example of a unit in which an increased or prolonged travel is given, a structure of the type shown in Figure 5 may be employed. In. this structure, the refrigerating unit per se, it will be understood, is positioned in the area R and the plenum chamber of such refrigeration unit extends over to the first passageway B'. The cooling area comprises the passageway B', which is in open communication with a narrow parallel passageway C', the latter in turn being connected to a similar parallel passageway D'. The passageway D' communicates with an angularly disposed passageway E', the latter being in'open communication with a series of parallel passageways F", G', H', I' and J As in the unit previously described, the products to be frozen enter at |06 and then pass, in the direction indicated by the arrows, in counterflow relationship to the flow of air, the entering products being contacted rst with the air at the higher temperatures and being contacted just prior to discharge from the apparatus (at I 0I) with air at the minimum temperature. Similarly, as shown in Figures 6 and 7, other modified forms of associated passageways may lbe utilized. Thus, as shown in Figure 6, `the refrigerating area may be comprised of a narrow, elongated passageway vB", which communicates with the angularly disposed passageway C". This latter in turn is connected serially with a series of parallel passageways, D", E", andy F", communieating with the passageway G", which is substantially parallel with passageway B". In vthis structure therefrigeration unit may be positioned comprise the Vconcept of achieved. In this manner, therefore,

and sharply differentiates of recirculation;v .X It Vwill be understood that, 'while specific em- In another embodiment of the invention, as shown in Figure 7, the refrigerating unit may be centrally located with respect to the 'refrigerating passaeways, as for example by being positioned v cles may be positioned at relatively more obtuse in the area R. vThe refrigeration space may bev `comprised of a series of parallel communicating passageways P. These are so respectively associated and correlated with the described refrigeration unitthat products entering at 300 are first contacted'with the warmer air and, imme diately prior to discharge at 36|, are contacted with air at the minimum temperature. The refrigeration unit R, as will be understood, 'is so associated with the cooling passageways that the air iserecycled through the unit, warm air being withdrawn from the last vpassageway P, circa- D lated through the refrigerator R, and discharged ,25 ticu1ar installation, and/or the market demands .l

into 'the irst passageway adjacent the discharge point 30|. These and other equivalent arrangements may be established, in each of which the refrigerating unit per se is mounted more or less centrally with respect to the passageways, and in which the coldest airafrom the refrigerating desired, the several passageways'which together constitute the entire .line of travel of the artiangles than those shown. While in the drawings, in the preferred embodiment, the passageway sections are shown at substantially right r angles to eachother, this is -given as merely illustrative of the principle of establishing the maximum length of travel for a given volumetric capacity.

Again, if desired, in order to insure a more streamlined iiow of the cooled air, the sharp corners at the intersections of the several passageways may be'illleted so as to diminish turbulence in these .areas and insure better control of the heat abstraction. J I Similarly, while theapparatus which has been illustrated involves the passage of the products 'to be refrigerated in the one horizontal plane..

it'wiil 'be understood that units may be devised in which such passage Iincludes an series of ver*- tical planesf'or a combination of verticalv and horizontal planes.

Again, depending upon the exigencies of a pardesired, -the several passageways may be illumiunit is passed countercurrent to the products to be'treated.

It will now be appreciated that a fundamental concept upon which the invention is Vbased is the idea of utilizing a bulk supply of air, continuously cooling this down by passing it in heat exchange relationship to the expansionv coil and extenu-` ating it into thinv streams so as to utilize it to contact with and abstract heat from the line of productsundergoing refrigeration. -Considered infanother aspect, the invention may' be said to ber into a markedly elongated, narrow passageway, not only is a^maximum lengthiof travel Aassured but, `because of the narrowness of the passageway, a much more effective controlrof the rate and the amount ,of heat abstraction is sible to secure anpptimum quantum heat extraction in a refrigerating relatively small area. cept ofthe present invention, a relatively.' small compact unit is thus made to serve the full funcand rate of tions of prior units of considerably greater'size.

The principle of this establishment of a bulk supply of 'the cooling medium tenuated stream, is characteristic ofthe method bodiments of theinventlon have been described. these have been givendidactically for the' purposeo'f explaining the underlying principles. As be appreciated, the'inv'ention, particularly in respecter the-apparatusgemployed, is susceptible of. considerable refinement. .'I'hus, if

exchange contacting it ifomlea'rlier systems t nated by the lights 96 which may appropriately be positioned, as at the corners of the passageways, so as to provide adequate lighting for constant inspection.

Yet again, if desired, ultraeviolet lamps, or

equivalent units, indicated 'diagrammatically at 91, may be employed so as to irradiate the products passing through the refrigerating unit to enhance the dietetic value of, and/or sterilize the Vproducts undergoing treatment.` If desired, also, ozonizers maybe utilized in the structure.

Wherever the circumstances so require, the

recirculating stream of refrigerated air may be establishing, in a re-v I caused to pass through air filters or other clariu fyingldevices to purify ,or deodorize it. Similarly, if desired ina particular case, the food products may be concomitantly seasoned and iefrigerated by introducingI a avoring principle,

K By utilizing this concept of, as it were, breaking up the refrigerating cham' chamber ofv In short, utilizing the con- J tied, across the wings `but' of utilizing'it,

for heat extraction purposea'in the form of ex' V35 preferably in the vapor phase, in controlled amounts into the refrigerated air system adjacent the pointof entry of the products.

Yet again, .the apparatus, as` be appreciated by those skilled in the art, may considerably* be renedas to its mechanical operation.

the apparatus may be provided, adjacent Y the feed and discharge doors 6l)y and 6i, with automatic feeding and discharge mechanisms respectively, ,i0 as to minimizeI handling-'of ther products and generally increase the eillciency of the unit. j For example, the chickens may be cord provided withaa loop whereby each chicken. or' other `unit, is suspended` from hookson the conveyor and in the 'spacedrelationship mentioned; Adjacent the discharge door, a knife or trip'mechanism which is associated with the conveyor drive may be utilized yto automatically s ever the suspension cord or remove the chicken from the hook. so that the frozen products rmay be deli'veredby gravityfto a chute to be transy ,ported to the packaging room. These and other" equivalent refinements fmay be utilized in the Anovel system and apparatus. Thus, while preferred embodiments of the in A vention have been described and indicated, it

will be .understood that the" invention itselfconceived'toreside in the broad iconcept ex@A or legs, with a string or pressed, and is not intended `to be limited to the structureshown, except as such limitations are clearly imposed by the appended claims.

I claim:

1. A refrigerating apparatus comprising a refrigeration unit, a refrigeration chamber; means to divide the chamber into a series of narrow. elongated passageways, a conveyor system extending through the passageways and adapted to transport products to be refrigerated therethrough means to force air in a cyclic stream in heat exchange relationship with the' refrigeration unit and thence through the said passageways and in a counter-current direction to the movement of the conveyor throughout the passageways.

2. A refrigeration apparatus for sharp freezing food products comprising a large insulated chamber, a series of partitions positioned in the chamber and cooperatively adapted to divide the chamber into a communicating series of relatively long, narrow passageways; an antechamber, a refrigeration apparatus having a portion thereof located in the antechamber, and having its expension coil in the said enlarged insulated chamber, and means cooperating 1with said partitions to continuously recycle air in heat exchange relationship to the expansion coil and thence through the series of passageways in a predetermined direction andat a predetermined velocity; means to convey a line of articles to be refrigerated through the said series of passageways and in a direction counter to the flow of air throughout their travel.

3. An apparatus for sharp freezing food products which comprises, an enlarged insulated chamber, in which articles may be refrigerated, a. refrigeration unit having a portion mounted adjacent the chamber and having an expansion coil thereof positioned within the chamber; means to divide the remainder of the said chamber into a series of long, narrow passageways so designed as to provide an optimum length of travel for a given volumetric size of the chamber; conveyor means mounted within the passageways; means cooperating with the first mentioned means .to positively recirculate air in a predetermined uni-directional flow and at a predetermined velocity through the passageways and in heat exchange relationship with the said expansion coil; to said conveyor means serving to transport products to be refrigerated through the passageways in a direction counter to the flow of air throughout their travel.

4. An apparatus for sharp freezing food products which comprises, an enlarged chamber in which articles may be refrigerated, an antechamber adjacent the insulated chamber, a refrigeration unit having a portion mounted in the antechamber and having an expansion coil thereof positioned within the insulated chamber; means to divide the remainder of said insulated chamber into a series of long, narrow passageways so designed as to provide an optimum length of travel for a given volumetric size of the chamber; conveyor means mounted within and movable through the passageways and the antechamber, means cooperating with the rst mentioned means to positively recirculate air in a predetermined uni-directional flow and at a predetermined velocity through the passageways and in heat exchange relationship with the said expansion coil;

said conveyor means serving to transport products to be refrigerated to the passageways in a direction counter to the flow of air throughout their travel.

OTTO C. BOTZ. 

